Loading patent…
AssigneeCummins Engine Company, Inc.
InventorsChung Y. Liu, Amarjit S. Ghuman, Benjamin M. Yen, Lester L. Peters, Edward D. Smith
Estimating the term…
Fuel injection rate shaping is integrated into the pressure intensification stage of a hydraulically actuated fuel injector having a pressure intensifier. In a first embodiment, the pressure intensification plunger is formed of two parts creating a damping chamber therebetween from which fluid is forced out through orifices in a lower one of the plunger parts during an initial phase of displacement of the upper part. Thus, injection will be performed initially at a lower pressure and rate, which increases once the plunger parts make contact. In a second embodiment, a throttled flow is set via a restrictor housing that telescopingly receives the upper plunger part, so that a lower injection rate occurs while fluid is bled off through a restricted flow path between the restrictor housing and the upper plunger part, and a higher injection rate is produced once a port in the upper plunger clears the restrictor housing. In a third embodiment, the two plunger parts of the intensifier have different areas relative to each other. In a fourth embodiment, flow to the intensifier plunger is varied by the intensifier plunger co-acting with a shaped inlet port increasing the effective area of the inlet port through which flow enters the intensifier as the intensifier plunger is displaced during its injection stroke. In a fifth embodiment, a throttling effect produced by a clearance between a protrusion on the intensifier plunger and a receiving bore in the intensifier body is used reduce the intensification effect during the initial phase of injection.
A hydraulically actuated fuel injector of the type having a metering and injection plunger mounted for reciprocation in a metering and injection chamber into which fuel to be injected is metered and from which a metered quantity of fuel is injected, a hydraulically actuated pressure intensifier with a pressure intensification plunger which acts on said metering and injection plunger for displacement thereof in an injection stroke for forcing fuel from said metering and injection chamber and out of said injector, said pressure intensification plunger having an effective surface area which is acted upon by a source of pressurized hydraulic fluid supplied to the injector that is greater than an effective area of said metering and injection plunger that acts on fuel disposed in said metering and injection chamber;
Dependencies are inferred from the claim text.